This invention relates in general to a boat hull and in particular to a boat hull configured for high speed planing operation.
Prior art boat hulls for use in high speed motor powered operation generally have been of two classes. The original planing hulls were flat bottomed since this shape gives minimum resistance and thus maximum hydrodynamic efficiency in the planing mode.
Flat bottom boat hulls have several disadvantages, however. In general they are unseaworthy, being quite unstable at low speeds, when turning, or in rough water since a flat bottom hull presents a different profile depending on the position of the hull in the water. In addition, flat hulls pound or slap during high speed operation even in relatively calm waters. The latter characteristic makes for an uncomfortable ride and over a period of time causes damage to the boat.
The second class of boat hulls is the deep V hulls. They comprise hulls having steep deadrise angles (deadrise angle is the angle which the bottom surfaces make with the horizontal), and chines positioned considerably above the at rest water line of the hull (chine is the juncture of the bottom surfaces and the sides). Deep V-hulls eliminate most of the seaworthiness problems associated with flat bottom hulls.
The major disadvantage of the deep V-hull is that the increased planing surface area inherent in the design greatly increases water friction. Thus larger and more powerful engines are necessary to bring the hull to a given speed.
In addition the deep V-hulls ride at a high bow-up attitude, particularly when accelerating and decelerating. Thus operator visibility is obscured by the bow, creating unsafe navigational conditions. Furthermore, they do not maintain a positive planing angle when in operation resulting in low lateral stability.
Also due to the high bow-up attitude and fast sink rate they are subject to swamping by backwash when rapidly decelerated.
Accordingly, it is the general purpose of the present invention to provide a boat hull for high speed planing operation which combines hydrodynamic efficiency and seaworthiness.
It is a further purpose of the present invention to provide such a boat hull that will plane at low speeds allowing use of lower powered engines, resulting in the saving of fuel.
It is a further purpose of the present invention to provide such a boat hull that planes at a small positive planing angle to provide good handling characteristics without pounding or slapping.
It is a further purpose of the present invention to provide such a boat hull wherein the planing angle remains nearly constant during acceleration and deceleration to increase operator visibility and to lessen the hazard of backwash.
It is a further purpose of the present invention to provide such a boat hull having outer chines positioned out of the water during high speed planing operation to prevent lunging of the hull in turns and to increase lateral stability.
It is a further purpose of the present invention to provide such a boat hull having reserve planing surfaces to maintain controlled lateral stability while turning.
It is a further purpose of the present invention to provide such a boat hull wherein the engine may be mounted in the keel at a location low in the hull minimizing propeller cavitation as well as providing increased stability at rest, during high speed planing and while turning.